Well pipe protector

ABSTRACT

A longitudinally split well pipe protector comprising an inner steel cylinder, an outer steel cylinder, a corrugated steel element therebetween, a rubber sleeve around the outer steel cylinder and latching means to hold the protector together.

United States Patent Sutko et al.

[ Dec. 30, 1975 WELL PIPE PROTECTOR Inventors: Adolph A. Sutko, Ponca City, Okla.;

George M. Myers, Houston, Tex.

Assignee: Continental Oil Company, Ponca City, Okla.

Filed: Sept. 19, 1974 Appl. No.: 507,318

US. Cl 308/4 A; 166/241; 175/325 Int. Cl. F16C 1/26 Field of Search 308/4 R, 4 A, 8.2, 237R, 308/237 A, 238; 175/325, 371; 166/241;

References Cited UNITED STATES PATENTS ll/l958 Medearis 308/4 A 3,094,360 6/1963 Collett 308/4 A 3,652,138 3/1972 Collett 3,741,252 6/1973 Williams 308/4 A X Primary Examiner-M. Henson Wood, Jr. Assistant ExaminerRandolph A. Reese Attorney, Agent, or FirmRichard W. Collins 3 Claims, 4 Drawing Figures U.S. Patent Dec. 30, 1975 FIGURE 2 FIGURE 4 FIGURE 3 FIGURE I WELL PIPE PROTECTOR BACKGROUND OF THE INVENTION a. Field of the Invention The present invention relates to an apparatus to protect well pipe such as drilling string and production tubing from abrading against the surrounding casing or borehole wall. More particularly the invention involves such an apparatus having improved strength characteristics against lateral forces.

b. Description of the Prior Art A well consists in general of a relatively small diameter borehole extending several thousands of feet into the earth. At least the upper portions of the borehole normally contains a metal casing cemented to the borehole sidewall. Sometimes the casing extends the entire length of the borehole. When a small diameter pipe, such as a drill string or production tubing is run into or out of the borehole, there is chance for contact between the pipe and the borehole or casing because of the comparative flexibility of the pipe due to its extreme length. Even after the pipe is positioned in the hole, it is subjected to forces during the drilling or pumping operations which may cause the pipe to bump or rub against the borehole or casing. This metal-tmetal contact can also result in damage to the pipe, the borehole, the casing or all three elements. The problem is especially severe at pipe collars which join sections of pipe together and which are slightly larger in diameter than the pipe itself.

Various types of well pipe protectors are known in the art. One protector is a split ring of rubber having a marcelled steel spring (i.e. having corrugations or undulations) molded into the rubber for strength. The protector can be opened to install it around the pipe. In other protectors the tubular rubber body is bonded to an inner cylindrical sleeve which can be locally corrugated to more securely engage the pipe. Other protectors are made in half sections held in place on the pipe by clamps. These protectors have not been entirely satisfactory, particularly from a strength standpoint. In certain parts of the borehole in which the lateral forces on the pipe are the largest, known protectors do not maintain a clearance between the pipe joints and the borehole sidewall or casing.

Accordingly, it is an object of this invention to provide a novel and improved well pipe and casing protector.

It is another object to provide a protector having simple, economical construction which is easily secured to an elongated member which is to be centered in a passage or hole.

It is a further object to provide such a protector having improved strength characteristics.

It is a still further object to provide such a protector which is larger in diameter than previous protectors.

It is also an object to provide such a protector which protects pipe in deviated holes.

Other objects, advantages and features will become apparent from the following detailed description and drawings.

BRIEF SUMMARY OF THE INVENTION A well pipe protector apparatus comprising: a. a longitudinally split inner steel cylinder sized to fit over a well pipe,

b. a longitudinally split outer steel cylinder concentric with and spaced from the inner steel cylinder,

c. a longitudinally split corrugated steel element in the annulus between the inner steel cylinder and the outer steel cylinder,

d. a longitudinally split rubber sleeve concentric with and surrounding the outer steel cylinder, and

e. latching means for securing the two longitudinally split elements together and holding the protector in tight engagement about the well pipe.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view showing one embodiment of the well pipe protector installed about a well pipe.

FIG. 2 is a section taken along the line 2-2 of FIG. 1.

FIG. 3 is a perspective view of the outer steel cylinder with the locking pins in position.

FIG. 4 is a detailed view of'the locking pin for the protector.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2 of the drawings, numeral 4 indicates the well pipe which is surrounded by the protector indicated generally at 6. Protector 6 has two diametrically opposite longitudinal splits 8 and 10 and is thus two half cylinders. Protector 6 is composed of inner steel cylinder 12 sized to fit tightly in non-slip engagement around well pipe 4. Outer steel cylinder 14 is concentric with and spaced from inner steel cylinder 12. The annular space between inner steel cylinder 12 and outer steel cylinder 14 is occupied by corrugated steel element 16. Outer steel cylinder 14 is surrounded by concentric rubber sleeve 18.

Referring now to FIGS. 3 and 4, protector 6 is positioned on well pipe 4 by placing the two half cylinders together around said well pipe 4 and securing the two half cylinders together with a locking means, such as with two locking pins 20. The longitudinal split ends of the two sections of outer steel cylinder 14 terminate in interlocking hooks 22 through which the two locking pins 20 are passed.

Corrugated steel element or cylindrical band 16 has corrugations or undulations running axially of the body and presenting crests which engage the outer surface of inner steel cylinder 12 and the inner surface of outer steel cylinder 14. Corrugated steel element 16 is preferably made of strong spring steel. It is corrugated steel element 16 which allows protector 6 to be made large in outside diameter with only a minimal increase in weight. The tendency for protector 6 to provide an obstruction around which drilling fluid is difficult to pass is reduced by the presence of corrugated steel element 16 which allows drilling fluid to pass therethrough.

It is preferred that the axial length of the split ring pipe saver or protector 6 be several times its wall thickness. The two semi-cylindrical or half sections of the composite protector 6 may be applied along the well pipe 4 at any desired location. It is generally preferable to position protector 6 close to the usual tool joint or coupling. Rubber sleeve 18 is a generally tubular body of sufficient thickness so that the outside diameter of protector 6 is larger than the outside diameter of the tool joint. Rubber sleeve 18 may optionally be of an equivalent elastomeric material which has adequate shock-absorbing characteristics. The overall outside diameter of protector 6 can also be varied by varying the diameter of outer steel cylinder 14 and the thickness of corrugated steel element 16. This provides a desirably relatively large outside diameter protector 6 with a relatively small increase in the weight of protector 6. It is preferred that the various elements of protector 6, i.e., inner steel cylinder 12, outer steel cylinder 14, corrugated steel element 16 and rubber sleeve 18 be bonded to each other, as by welding in the case of the metal parts or by use of adhesives. It is preferred that rubber sleeve 18 have at its ends beveled shoulders 24 which slope outwardly and toward the middle to provide guide surfaces for guiding protector 6 during its movement longitudinally through the borehole or casing.

Various locking means can be used to secure together the two half sections of protector 6. One locking means illustrated in the Figures consists of a plurality of interlocking hooks or eyelets 22 formed on the longitudinally split ends of the two half sections of outer steel cylinder 14. When the two half sections are joined about well pipe 4, tapered locking pins 20 are inserted through interlocked eyelets 22. Other locking means include clamps, such as flexible tension clamps (not shown), positioned around exposed ends 26 of outer steel cylinder 14. The clamps are held together with a hinge pin, cotter key or other suitable fastening device passed through aperatures in the clamps. Another locking means comprises providing the lateral surface ends of each split segment of outer steel cylinder 14 with short outwardly projecting fingers. The fingers may be either interlocking or abutting. When the two segments of outer steel cylinder 14 are positioned about well pipe 4, a retainer plate is slipped lengthwise over the two sets of fingers to hold said two sets of fingers together. The retainer plate is a rigid U-shaped plate with the opening of the U of sufficient width to accommodate the fingers. I

The above disclosure represents certain preferred forms of the apparatus of this invention. It will be understood that various modifications and alternatives may be adopted by those skilled in the art which are within the scope of the appended claims without departing from the spirit of the invention.

We claim:

1. A well pipe protector comprising:

a. an inner steel cylinder having two diametrically opposite longitudinal splits, said inner steel cylinder sized to fit tightly about the well pipe;

b. an outer steel cylinder having two diametrically opposite longitudinal splits, said outer steel cylinder being concentric with and encompassing said inner steel cylinder to provide an annular space therebetween;

c. a corrugated steel cylindrical band having two diametrically opposite longitudinal splits therein, said corrugated steel cylindrical band being positioned in the annular space between said inner and outer steel cylinders, having corrugations running axially of the protector, presenting crests which alternately engage the outer surface of the inner steel cylinder and the inner surface of the outer steel cylinder, being bonded to the inner and the outer steel cylinders, and allowing for flow of fluid axially between said inner and outer steel cylinders;

d. an elastomeric sleeve having two diametrically opposite longitudinal splits therein, said sleeve surrounding and being bonded to the outer steel cylinder and concentric therewith;

e. said inner steel cylinder, outer steel cylinder, corrugated steel cylindrical band and elastomeric sleeve all with two diametrically opposite longitudinal splits providing two semi-cylindrical half sections, and

f. latching means for joining the two semi-cylindrical half sections of the protector about a well pipe.

2. The apparatus of claim 1 wherein the latching means is attached to the outer steel cylinder.

3. The apparatus of claim 1 wherein the latching means comprises a plurality of interlocking eyelets formed on the longitudinally split ends of the outer steel cylinder and a locking pin. 

1. A WELL PIPE PROTECTOR COMPRISING: A. AN INNER STEEL CYLINDER HAVING TWO DIAMETRICALLY OPPOSITE LONGITUDINAL SPLITS, SAID INNER STEEL CYLINDER SIZED TO FIT TIGHTLY ABOUT THE WELL PIPE; B. AN OUTER STEEL CYLINDER HAVING TWO DIAMETRICALLY OPPOSITE LONGITUDINAL SPLITS, SAID OUTER STEEL CYLINDER BEING CONCENTRIC WITH AND ENCOMPASSING SAID INNER STEEL CYLINDER TO PROVIDE AN ANNULAR SPACE THEREBETWEEN; C. A CORRUGATED STEEL CYLINDRICAL BAND HAVING TWO DIAMETRICALLY OPPOSITE LONGITUDINAL SPLITS THEREIN, SAID CORRUGATED STEEL CYLINDRICAL BAND BEING POSITIONED IN THE ANNULAR SPACE BETWEEN SAID INNER AND OUTER STEEL CYLINDERS, HAVING CORRUGATIONS RUNNING AXIALLY OF THE PROTECTOR, PRESENTING CRESTS WHICH ALTERNATELY ENGAGE THE OUTER SURFACE OF THE INNER STEEL CYLINDER AND THE INNER SURFACE OF THE OUTER STEEL CYLINDER, BEING BONDED TO THE INNER AND THE OUTER STEEL CYLINDERS, AND ALLOWING FOR FLOW OF FLUID AXIALLY BETWEEN SAID INNER AND OUTER STEEL CYLINDERS; D. AN ELASTOMERIC SLEEVE HAVING TWO DIAMETRICALLY OPPOSITE LONGITUDINAL SPLITS THEREIN, SAID SLEEVE SURROUNDING AND BEING BONDED TO THE OUTER STEEL CYLINDER AND CONCENTRIC THEREWITH; E. SAID INNER STEEL CYLINDER, OUTER STEEL CYLINDER, CORRUGATED STEEL CYLINDRICAL BAND AND ELASTOMERIC SLEEVE ALL WITH TWO DIAMETRICALLY OPPOSITE LONGITUDINAL SPLITS PROVIDING TWO SEMI-CYLINDRICAL HALF SECTIONS, AND F. LATCHING MEANS FOR JOINING THE TWO SEMI-CYLINDRICAL HALF SECTIONS OF THE PROTECTOR ABOUT A WELL PIPE.
 2. The apparatus of claim 1 wherein the latching means is attached to the outer steel cylinder.
 3. The apparatus of claim 1 wherein the latching means comprises a plurality of interlocking eyelets formed on the longitudinally split ends of the outer steel cylinder and a locking pin. 